Four-wheel drive vehicles provide improved traction on roads such as those covered in snow, ice, and mud. Four-wheel drive vehicles may be provided with an axle shift mechanism to selectively disconnect a secondary driving axle in order to provide a two-wheel drive mode when using four-wheel drive mode is not beneficial. Some four-wheel drive axle shift mechanisms may utilize axle gear lubricant to lubricate the shift mechanism. However, in some low temperature conditions, it may be difficult for the four-wheel drive shift to occur due to drag that may result from the cold, lower viscosity axle gear lube.